Signaling system.



G. W. KUHN.

SIGNALING SYSTEM.

, APPLICATION FILED AUG-27, i917 1,279,882, PatentedSept. 24,1918..

1V VEN TOR mim @gorge W] VMKM ATTORNEY UNITED STATES PATENT oEErcE.

GEORG W. KUHN, OF BROOKLYN, NW YORK, ASSIGNOR TO AMERICAN TELEPHONE AND TELEGRAPI-I COMPANY, A CORPORATION OF NEW YORK.

SIGNALING SYSTEM.

Specification of Letters Patent.

Patented Sept. 24, 1918.

Continuation in part of application filed March 29, 1915, Serial No. 17,697. This application led August 27,

1917. Serial No. 188,346.

To all Iwhom t may concern:

Be it known that I, GEORGE W. KUHN, residing atBrooklyn, in the county of Kings and State of New York, have invented certain Improvements in Signaling Systems, of which the following is a specification.

This invention relates to signaling systems, and particularly to those in which' This 'application is filed as a substitute for.

my original application Serial No. 17,697 filed March 29, 1915, and is a continuation thereof with respect to the subject matter common to the two applications.

The principal objects of the invention are to provide a system giving a tone effective for this purpose, and applied to the receiver in such a manner that it would not cause disagreeable results if the subscriber chanced to have the receiver at his ear.

The accompanying drawingrepresents diagrannnatically. one arrangement by which the invention'may be carried out. At A appears the usualapparatus and circuit of a telephone substation united by a line L to its answering jack J at the central station and to line equipment -thereat. Inaddition to the customary line-connecting cord circuits, each operator may be provided with a special cord circuit C having a plug P for cooperation with the jack J and receiving talking current through a repeating coil I from the central station battery B. This cord circuit is shown as including a key K Jfor connecting the operators telephone set thereto and having a supervisory lamp O'controlled by a relay R, which elements, however, are not directly concerned with this invention.

Associated with the cord C is a source of intermittent current suitable for generating a signaling tone. This may be of such a character as to give alternating current, but it appears here as a rotary interrupter H continuously driven from some sourcel of power, to the conducting segments of which interrupter battery is connected, and from which the current impulses are taken ofi by a brush or wiper. The character of the tone 1s determined independently of the interrupter by a controlling apparatus comprising a contact device D and a plurality of resistances associated with the primary winding of the induction coil T. The -contact device D is illustrated as a circumferential series of fixed contacts 10 over which travels a brush or movable contact member 11 under theA iniiuence of some power means, as a springl2, which is wound by the operator, and upon its release causes the brush automatically to pass over all the contacts 10 acertain number of times. The fixed contacts 10 of the contact device D are shown connected with terminals 25, 14:, etc. of graduated resistances of decreasing value downward, the opposlteterminals of which are connected with the primary Winding 18 of said induction coil having its secondary connected as shown in the talking circuit. e A pick-up interrupterE is located in the initial energizing circuit of relay R3 and adapted to rotate synchronously with the brush 11 of the interrupter device D to insure that a. weak tone is produced in the subscribers receiverv at the `time of first connecting the howler equipment to the line. When the operator inserts the plug P in jack J and depresses key K2, relay R3 is energizedxas soon as the piek-up interrupter E reaches a position where the two brushes rest upon the same metallic segment, and thereby closes at contact 21 the circuit through primary winding 13 and interrupter H. Due to the fixed relation existing between the pick-up interrupter E and the brush l1 of contact device D, the twovbrushes of interrupter E will rest on the same metallic contact of said interrupter only when the brush 11 rests on contact 10a, and consequently relay R3 will be energized, and the primary circuit will be closed through contact 21 only at .that in'- stant when the maximum resistance is connected in series with interrupter H, and the minimumcurrent is flowing through said prlmary circuit. .e

It will be seen that the graduatedV resistances Q5, 14, etc. are successively introduced into this circuit as brush 11 advances from contact to contact, each resistance, being less than the preceding one, and thereby increasingthe current strength in winding 13 and inductively the current strength in the talking circuit, and consequently the volume of the tone in the subscribers receiver.

The nature of the invention will be' seen more clearly from the following description of the operation of the system :-It being observed from the condition of the signals associated with the line L'o substation A that the subscriber has neglected to replace the receiver upon its hook, the operator, wire chief, or other attendant at the central station inserts the plug P of cord C in a jack of the line, as J, depresses key K2 and makes ready the contact device D. When the plug P was inserted in j'ack J, the circuit was closed through the winding of relay R2, sleeve contacts of plug P and jack J and winding of the cut-off relay R4, whereby both relayR2 and relay R2 are energized. Relay R2 contact 15 and lamJp O, thereby tending to cause the said lam to light, but its lighting key K2, winding ,line L and substation .lay R3 is locked up over a .circuit through is prevented by t e operation of relay R which is energized by current flowing through a circuit from battery B, conductor 28, winding of relay R, conductor 29, ring contacts of plug P and jack J through the A, tip contacts of jack J and plug P and conductor 30 to ground. Relay R is thereby energized, which closes a circuit through its front contact which short circuits lamp O and thereby prevents its lighting. 1f the two brushes of the pick-up interrupter E are upon the same metallic segment, a circuit is closed through contact 15 of relay R2, winding of relay R3, interrupter E, conductor 2'6, contact 16 of 17 of repeating coil I to round, whereby relay R3 isy energized. Re-

by a current which flows contact 15, the windand contact 20 of relay R3, 4conductor 27, and contact 19 of key K2. At its front contact 21 relay R3 closes the circuit of the primary 13 of'induction coil T and the interrupter H. The current' impulses through the primary cause corresponding impulses in the secondary, the effect of which upon the substation circuit depends upon which contact 10 of the device D its brush 11 has reached. Assuming the brush to be upon ing the next contact following the normal contact 10a (movement being in direction of the arrow) a comparatively feeble tone impulse will flow from terminal 22 of the induction coil secondary through condenser 23 A (which prevents the passage of battery current through the secondary of the induction coil), contact 24 of key K2, ring contacts of plug P and jack J over the line L and through the winding of the receiver at A, tip contacts of the jack J and plug P, conductor 30, contactV 16 of key K2 to the other terminal of the secondary of induction coil T.

the current 1n closes a circuit through viously traced On account, of the relatively largelre-*istance represented by resistance 25 which is in series with the primary of the induction coil, a relatively small amount of current will iow through the said primary so that a relatively smlall current is induced in the secondary, and consequently the impulses will affect the diaphragm of the receiver only slightly..

that the current strength through the primary increases .in value and consecpuently the secondary gradually increases in intensity until it reaches its maximum value when the brush is on a contact As the brush advances, the V `successive 'resistances diminish 1n value so 10 next preceding the contact 102. The cur.- v

rent then begins again at its minimum, repeating the cycle as long as the power means 12 is operative. When the receiver at substation A is replaced upon its switchhook, the circuit previously traced through the winding of re- R is opened, whereby relay R is deenergized and its front contact opened, thereb removing the short circuit around lamp g, thus permitting said lamp to glow brightly. Upon the receipt of this signal, indicating placed upon its hook, the operator restores key K2 to its normal position, thereby opening at contacts 16 and24 the circuit preing at contact .19 the circuit previously traced through the winding .and contact 20 of relay R3, whereby the circuit through the primary winding 13 and interrupter H is opened. When' the operator removes plug P from jack J, the signaling system is restored thereby to its normal inoperative condition.

It will thus be seen that an eficient attention-attracting signal of gradually varying volume is attained, the initial application of which to the substation line is always when it is feeblest, so that if the subscriber has applied the receiver to his ear just be fore the plug P is placed in the line jack he can remove'it before the strength o the tone makes the effect unpleasant.

What is claimed is:

1. The combination with a subscribers telephone line, of means for applying signaling current thereto, means for automatically and gradually varying the effective strength of said current, and means whereby the period of application of said current may be limited.

2.. The combination with a subscribers telephone line provided with a receiver, o means for applying signaling current thereto, and means for automatically and alternately varying the effective strength ci said current for increasing and decreasing the intensity of tone produced by said receiver.-

that saidreceiver has been re- A through the secondary of induction coil T and the line L, and also open- ,of tone-generating means,

3. In a signaling system, aA circuit including a source of signaling current, and means for automatically and gradually varying the effective strength of said current, and means operated by said current-varying means for controlling said circuit and for rendering said source of signaling current effective at a predetermined strength of current.

4. The combination with tone producing means. of means for automatically varying said tone between a minimum and a maximum, and other means operated by said tone- `varying means for rendering the tone producing means initially effective to produce a tone of minimum intensity.

The combination with a substation line, of a source of signaling current and controlling means therefor, a connecting circuit for applying the signaling current to the substation line, and switching means under thc joint influence of the controlling means and connecting circuit for rendering the signaling current effective.

The combination with a substation line, of'a source of signaling current and controlling means for gradually varying the strength of said current, a connecting circuit for applying the signaling current to the substation line, and switching means operable when the connecting circuit is joined to the substation line and the controlling means is in a particular position for rendering the signaling current eifective.

7. The combination with a substation line,

means for gradually varying the intensity'of the tone, a connecting circuit for the' tone-generating means and substation line, an electromagnetic switching device .for rendering the tone effective, and a circuit for said switching device including contacts closed when the connecting circuit is joined to the substation line and the tone is of a minimum intensity.

8. lA tone-generating means. intensity varying means therefor provided with contacts, a connecting circuit with which the tone-generating means is associated, a relay for rendering said tone-generating means effective in said circuit, and an energizing circuit for the relay extending through contacts of the intensity varying means when the tone is of predetermined intensity.

9. A tone-generating means, controlling means therefor provided with contacts, a connecting circuit with which the tone-generating means is associated, a relay for rendering said tone-generating means effective in said circuit, an energizing circuit for the relay extending through contacts of the controlling means in its initial position, and a locking circuit for the relay independent of the controlling means.

10. The combination with a subscribers telephone line and receiver, of means for applying a signaling current thereto whereby said receiver is made to produce an audible warning signal, and automatic means for gradually varying the eEective strength of said signaling current.

l1. The combination with a subscribers telephone line and receiver, means whereby said receiver is made to produce an audible warning signal, and means for automatically varying the intensity of said audible signal.

12. The combination with a subscribers telephone line and receiver, means whereby said receiver is made to produce an audible warning signal, automatic means for varying the intensity of said signal, and means for rendering the signal effective at a predetermined intensity. 4

In testimony whereof, I have signed m name to this specification this fourteentli day of August 1917.

GEORGE W. KUHN. 

